Welcome to the second module of the course that is fundamental of software defined radio in the previous
module, we have studied about the communication blog.
We have also discovered that software defined use definition, the basic architecture, its advantage
history.
And we have also studies about the relation of radios we have discussed about this communication architecture.
We have we have covered the software defined networking.
Moreover, we have also covered the different communications standards and signals along with the decimal
unit.
In this module, too, we are going to discuss the software defined or do have the architecture.
Moreover, we will also do a deeper understanding of this.
Jerrard.
We will also discuss the impediments in the software defined use and we will cover the different companies
who manufacture this year and last year.
And based on several criteria, they will try to pick the best Asgeir suited for our purpose.
So let's start.
So after completing the module one, we can see that this year consists of two parts.
The first part is the discrete distilled base bird section of this year, and the second part is the
analog or other front end or the very poor section of the Asgeir.
So in the discrete or digital section, we have the D.
We have that video.
We have the combination of the both and in the part of the outer front section.
And it's a completely analog system.
And based on that, our front end system, there can be two types of architecture.
One is the architectural section within the modern architecture.
So you can see here the baseband part is same for all the architecture.
It might be a disparate project based on the different out different and topologies that Asgeir hardware
architecture find.
It is towline software defined in your home, software defined.
You do architecture.
And this is a typical example of as Dearborne, we will discuss in detail in the successive lectures
before moving to more detail.
We will discuss some very, very basic concepts which will be useful to understand the hardware architecture.
So the first concept we are going to discuss is the receiver selectivity.
So the receiver selected is a very important parameter and it is the ability of a receiver to select
a desired signal in the presence of other unwanted signal.
Suppose we have transmitted a signal.
Let's say my signal was this one.
This was the signal.
This is the frequency domain.
The Silvy signal is one.
And it was transmitted through an antenna.
And the receiver said, I have received the signal when I brought the spectrum of this signal, the
receiver, what we will see, we will have multiple signals.
For example, we have a signal as one and we have some other signals like as to or we have some other
signals like a stream.
So if my receiver can do the digital signal or it can tune out, it can capture the desired signal,
then discarded activity.
So the names are used.
If a receiver can properly select the desert signal, the selectivity is good.
Suppose I want to capture the signal as to and I and I can select it using my receiver, then my receiver.
Selectivity is good.
So basically receiver selectivity is an ability of the receiver to set up their desired signals in the
presence of unwanted signal.
Or you can say in the presence of any signal that is called receiver selectivity.
So the next important term is the receiver sensitivity.
So suppose we have received the signal.
We have a multiple signal.
For example, this is a signal.
This is also a signal.
We have a lot of signals.
So these are some signals.
So what a receiver sensitivity suggests it is a low signal power level and the input of a receiver which
guarantees proper working off of a receiver.
So I suppose if I can capture the signal and wait to see what is work, so then it is receiver sensitivity.
So this is the minimum power which of which I can choose and my receiver will work effectively.
So if you do, suppose we load the load and then my receiver is thought to be able to sense this signal.
So the receiver sensitivity as the name suggests.
So it is a power level or the input of receiver next to the frequency mixer.
So Frequency Miksad is a simple device.
It has an input called it has a output port and it has a lot, a lot easier local oscillator.
So it is a three foot device.
So using input and l'eau we can provide to signal at the mixer.
And he will receive a new signal to do receive signal, maybe just some of the signals or it may be
the difference of the signal.
Suppose my input frequency signal was EF1 and signal frequency was F a low.
So the output of this device, I am going to receive a signal that is the combination of F one plus
F hello.
And the second signal, will we have one?
Minus F, I know, so we're going to receive some of the signals and we will see the difference between
the signal and suppose we want to use this signal and we want to discard the signal, then we use a
band pass filter here using a band possible that we can use this signal.
This process is also called a conversion caused by actual input frequency of the signal was EF1 and
it was converted to a for plus a fellow.
And this is called CALDA Down conversion process, because my signal frequency is going to be reduced
compared to this one.
So the frequency mixer can be used for the translation of a frequency.
In the case of practical frequency Mixu, there may be also some component with the grid there.
Like I suppose this is the full-price have a little we have some components also applicable in the case
of particle Mixu.
So we can say that it is a device which is used to receive signals from one frequency range to another.
And this shifting is also known as Hedra dining, for example, in Superhit, trying to see what a mixture
is used to translate to receive signal to an intermediate frequency signal, or it is used to modulate
a carrier signal in the radio transmitter.
So these are the two primary application of frequency Mixu and we will encounter these applications
in the subsequent lectures.
Next, the very important thing, we are going to learn the quadrature modulation.
So suppose we have we have a complex signal as we have started earlier.
Suppose we have a signal exit and it is given as a E to the power G Omega D.
So this signal consists of a two part.
They can also try to test x G equals x, r, t.
That is the real part and plus G X..
I think that is the imaginary part.
We can also write this as like as it.
Course.
Tita Dee, and this can be written as a tea sign.
Teacher team, so this is the real part, this is the real part, this is the imagery part.
So based on this, we do find a component head to component.
You can see here supports my local authorities saying bigger city, so this section is accepting signal
of the 90 degree phase shift that is called that is called quadrature Festo suppose so.
There are 90 degree face shifted from each other.
So that's why they're they're called quadrature face.
You can see in the waveform also, we have a two different waveform.
That is our sign one and the cosine one.
So if these two waveform are modulated and combined with different amplitude and so on, the combination
of these two waveform, my amplitude is going to change.
But the thing is, you can see here, this is my same part.
This is my sorry, this is my cosine for this same part.
So you can see here.
Exactly.
There is a 90 degree phase shift between these two.
There's the name is called Quadrature Modulation.
So after modulating the real part and as well as the new part, what we do, we combine the signal.
So we have, again, a complex signal which is available for the transmission.
So what we are doing here, we are transmitting the silent cosine is really and when we combine them,
they get that different employees to values.
So in this module, we have covered as dear hardware, we have covered the sensitivity means how the
minimum, the strength of the signal can be detected.
We have studied the selectivity.
We have studied the frequency miksa, as well as the quadrature modulation.
So next we are going to learn the supersaturated architecture.